IHL and Words

[life24]

Hello,
In Header length of IPv4 we have 4 bit and each bit is 32 bit words.
What means words here?
That means each bit point to 32 bit?
1111 * 32 bit = 480 bit

Thanks

 

[Gryz]

The header length is in units of 4.
So when the header length is 15 (1111 in binary) then the actual length of the header = 15 * 4 = 60 bytes. Normal header (without options) is 20 bytes, so you will normally see 20/4 = 5 in that field. 99.9999% of all IP packets start with 0x45 (mean IP version 4, headerlength 5x4=20).

Google for a program called Wireshark.
It's free. Download and install it.
With WireShark you can actual look at real packets, being sent from and to your own PC.
Very interesting and educational.